This game is... disappointing. The strategy has been replaced with grinding. Some of the side missions are impossible to do if you haven't been able to find any heroes of a specific element. And heroes that only have melee units are all but useless on 90% of the missions.
The first 3 Protector games were fantastic.
@ Shushoto
Thanks. I had that setup on my other path, except on the initial straightaway I had the lvl 2 down ramp followed by the lvl 1 up ramp and had a couple of treadmills after the first turn. Still have no idea why neither of my paths worked.
I can't do lvl 29. I have created 2 different paths, one which does not use all the pieces (it has one lvl 2 block left over) and another using PuzzleFailure's suggestion of a bridge midway up on 2 lvl 2 blocks. Neither path has enough power to get the ball high enough.
Here's a screenshot of one of the paths: http://www.flickr.com/photos/43175729@N03/4365328119/
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 "Protector IV"){kind=icon}
 "VVVVVV Demo"){kind=icon}
 "Isoball 2"){kind=icon}
 "Cover Orange 2"){kind=icon}